The soleus muscle is a monoarticular plantarflexor
composed slow-twitch fatigue-resistant muscle fibers. Through its
attachment to the proximal tibia, contraction of the soleus muscle
in a closed kinetic chain (when the foot is planted) produces a
posterior pulling force on the posterior proximal tibia. The
anterior cruciate ligament (ACL) is responsible for preventing
anterior displacement of the tibia relative to the femur. Through
the production of a posterior pulling force on the tibia, soleus
muscle contraction in a closed kinetic chain could help reduce
strain on the ACL. Fatigue is a neuromuscular phenomenon that can
alter biomechanical strategies during athletics and can increase an
individual’s risk of being injured. The purpose of this study is to
analyze the effects soleus muscle fatigue has on knee biomechanics
during the sidestep cutting maneuvers. To analyze the effects of
soleus muscle fatigue, thirteen female subjects underwent a
submaximal fatigue protocol targeting the soleus muscle.
Biomechanical data during sidestep cutting tasks were gathered for
pre-/post-soleus fatigue conditions. Additionally,
dominant/nondominant limb differences were secondarily analyzed.
Results showed a significant increase in peak knee extension moment
in the post-soleus fatigue condition during the sidestep cutting
task. We concluded that fatigue or excessive stretch of the soleus
muscle puts the ACL at an increased risk for injury during sidestep
cutting maneuvers. These findings provide evidence that the tricep
surae muscles have an influence on knee biomechanics during dynamic
exercise. Further investigation of these factors can help with the
development of ACL injury prevention and rehabilitation
strategies.
Advisors/Committee Members: Froehle, Andrew (Advisor).